The calculated distance (air line) between Sarpol-e Z̄ahāb and Darreh Shahr is approximately 126 miles respectively 203 kilometers.
By car or train, the actual journey to Darreh Shahr is certainly longer, as only the direct route (as the crow flies) between Sarpol-e Z̄ahāb and Darreh Shahr has been calculated here.
Air line (approximately)
203 kilometers
109 nautical miles